A Comparative Study On Dento-arch Morphology For Adult Unoperated And Operated Cleft Palate Paitients

Objective To investigate the effects of cleft palate and operation on the development of dental-arch morphology in UCLP patientsMethods Thirty UCLP patients who received lip repairing at 3 months～2 years old and palate repairing at 4～6 years old were included in the operated group. Unoperated group consists of 30 UCLP patients with only lip repaired at 3 months～2 years old. 30 individuals with normal occlusion serve as control group. Three groups are matched for gender and age.Dental study model was made for each subject. 90 stone casts were scanned by helical CT and captured a series digital sliced radiographs of them. The program which was developed by Visual C 6.0 language rebuilt the 3D graphics and measured the width, length, height of the dental arch, the inclination and area of palatal shelf.The intermaxillary relationship was recorded. The results of measurement were analyzed with ANOVA.Results (1) In the operated group, all the measurements of maxillary width, height and anterior length are significantly smaller than the normal group except the width between maxillary tuberosity and second molar and the posterior length. The upper arch ratio shows that in operated group the mean inter-canine width is only 44.2% of the-inter-second molar width, while in the untreated group this value is 50.23% and in the control group even 63.04%.The mandibular dental arch width and length are not statistically different from the control group.(2) In the unoperated group, all the measurements of maxillary width, length and height are significantly larger than those in the operated group. The width of maxillary inter-first premolar region is statistically narrower in unoperated group than that in normal group. At the level of canine this difference is even more obvious. As far as the inter-first molar and the inter-second premolar width are concerned, the width of the unoperated group is not significantly different from the control group and gradually decreases. The maxillary width at the level of the second molar and tuberosity are markedly larger compared to the control group. Palatal area is obviously smaller than normal whereas palatal height and inclination is higher. Up to the level of the second premolar the transversal dimensions of the mandible of unoperated group are not significantly different from that of noncleft population while at the level of first-molar and second-molar, the mandible is wider than the latter.The lengths of the maxillary and mandible dental arch reduce significantly than the normal group.(3)The crossbite rate in anterior region of operated group is 93.3% in contrast to 36.7% of unoperated group, while the crossbite rate in posterior region is 96.7% in contrast to 6.7%.Conclusion (1) Palate surgery is the main reason contributing to the development deficiency of maxillary dental arch in each dimension except for the posterior length. The presence of a cleft has an influence on the final development of the dento-alveolar part of the maxilla and the influence is limited to the vicinity of the cleft in the anterior region.(2)lip surgery inhibits the forward growth of the maxillary dental arch. It reducees the width and length of anterior region.(3) There is congenital development deficiency of palate tissue in cleft palate patient and palatal shelf positions more cranially.